Q&A Hero

Q: In an opinion survey, a random sample of 1,000 adults from the United States and 1,000 adults from Germany were asked whether they supported the death penalty. 590 American adults and 560 German adults indicated that they supported the death penalty. The researcher wants to know whether there is sufficient evidence to conclude that the proportion of adults who support the death penalty is higher in the United States than in Germany. What is the p-value for this test?

Q: In an opinion survey, a random sample of 1,000 adults from the United States and 1,000 adults from Germany were asked whether they supported the death penalty. 590 American adults and 560 German adults indicated that they supported the death penalty. The researcher wants to know whether there is sufficient evidence to conclude that the proportion of adults who support the death penalty is higher in the United States than in Germany. What is the decision at = .05?

Q: In an opinion survey, a random sample of 1,000 adults from the United States and 1,000 adults from Germany were asked whether they supported the death penalty. 590 American adults and 560 German adults indicated that they supported the death penalty. The researcher wants to know whether there is sufficient evidence to conclude that the proportion of adults who support the death penalty is higher in the United States than in Germany. What is the decision at = .10?

Q: In an opinion survey, a random sample of 1,000 adults from the United States and 1,000 adults from Germany were asked whether they supported the death penalty. 590 American adults and 560 German adults indicated that they supported the death penalty. The researcher wants to know whether there is sufficient evidence to conclude that the proportion of adults who support the death penalty is higher in the United States than in Germany. What is the sample value of the test statistic?

Q: In an opinion survey, a random sample of 1,000 adults from the United States and 1,000 adults from Germany were asked whether they supported the death penalty. 590 American adults and 560 German adults indicated that they supported the death penalty. The researcher wants to know whether there is sufficient evidence to conclude that the proportion of adults who support the death penalty is higher in the United States than in Germany. What is the rejection point (critical value of the test statistic) at = .05?

Q: In an opinion survey, a random sample of 1,000 adults from the United States and 1,000 adults from Germany were asked whether they supported the death penalty. 590 American adults and 560 German adults indicated that they supported the death penalty. The researcher wants to know whether there is sufficient evidence to conclude that the proportion of adults who support the death penalty is higher in the United States than in Germany. What is the rejection point (critical value of the test statistic) at = .10?

Q: A fast food company uses two management-training methods. Method 1 is a traditional method of training, and Method 2 is a new and innovative method. The company has just hired 31 new management trainees. 15 of the trainees are randomly selected and assigned to the first method, and the remaining 16 trainees are assigned to the second training method. After three months of training, the management trainees take a standardized test. The test was designed to evaluate their performance and learning from training. The sample mean score and sample standard deviation of the two methods are given below. The management wants to determine if the company should implement the new training method.Is there evidence at = .01 to conclude that the new training method is more effective than the traditional training method?

Q: A fast food company uses two management-training methods. Method 1 is a traditional method of training, and Method 2 is a new and innovative method. The company has just hired 31 new management trainees. 15 of the trainees are randomly selected and assigned to the first method, and the remaining 16 trainees are assigned to the second training method. After three months of training, the management trainees take a standardized test. The test was designed to evaluate their performance and learning from training. The sample mean score and sample standard deviation of the two methods are given below. The management wants to determine if the company should implement the new training method. Mean Standard deviationMethod 1 69 3.4Method 2 72 3.8Is there evidence at = .05 to conclude that the new training method is more effective than the traditional training method?

Q: A fast food company uses two management-training methods. Method 1 is a traditional method of training, and Method 2 is a new and innovative method. The company has just hired 31 new management trainees. 15 of the trainees are randomly selected and assigned to the first method, and the remaining 16 trainees are assigned to the second training method. After three months of training, the management trainees take a standardized test. The test was designed to evaluate their performance and learning from training. The sample mean score and sample standard deviation of the two methods are given below. The management wants to determine if the company should implement the new training method.What is the sample value of the test statistic?

Q: A fast food company uses two management-training methods. Method 1 is a traditional method of training, and Method 2 is a new and innovative method. The company has just hired 31 new management trainees. 15 of the trainees are randomly selected and assigned to the first method, and the remaining 16 trainees are assigned to the second training method. After three months of training, the management trainees take a standardized test. The test was designed to evaluate their performance and learning from training. The sample mean score and sample standard deviation of the two methods are given below. The management wants to determine if the company should implement the new training method.What is the absolute value of the rejection point (critical value of the test statistic) at = .01?

Q: A fast-food company uses two management-training methods. Method 1 is a traditional method of training, and Method 2 is a new and innovative method. The company has just hired 31 new management trainees. 15 of the trainees are randomly selected and assigned to Method 1, and the remaining 16 trainees are assigned to Method 2. After three months of training, the management trainees take a standardized test. The test is designed to evaluate their performance and learning from the training. The sample mean score and sample standard deviation of the two methods are given below. Company management wants to determine whether the company should implement the new training method.What is the absolute value of the rejection point (critical value of the test statistic) at = .05?

Q: A fast-food company uses two management-training methods. Method 1 is a traditional method of training, and Method 2 is a new and innovative method. The company has just hired 31 new management trainees. 15 of the trainees are randomly selected and assigned to Method 1, and the remaining 16 trainees are assigned to Method 2. After three months of training, the management trainees take a standardized test. The test is designed to evaluate their performance and learning from the training. The sample mean score and sample standard deviation of the two methods are given below. Company management wants to determine whether the company should implement the new training method.Write the null and alternative hypotheses.

Q: Let p1 represent the population proportion of U.S. senatorial and congressional (House of Representatives) Democrats who are in favor of a new modest tax on junk food. Let p2 represent the population proportion of U.S. senatorial and congressional Republicans who are in favor of a new modest tax on junk food. Out of the 265 Democratic senators and members of Congress, 106 of them are in favor of a junk food tax. Out of the 285 Republican senators and members of Congress, only 57 are in favor a junk food tax. At = .01, can we conclude that the proportion of Democrats who favor a junk food tax is more than 5 percent higher than the proportion of Republicans who favor the new tax (using critical value rules)?

Q: Let p1 represent the population proportion of U.S. senatorial and congressional (House of Representatives) Democrats who are in favor of a new modest tax on junk food. Let p2 represent the population proportion of U.S. senatorial and congressional Republicans who are in favor of a new modest tax on junk food. Out of the 265 Democratic senators and members of Congress, 106 of them are in favor of a junk food tax. Out of the 285 Republican senators and members of Congress, only 57 are in favor of a junk food tax. Find a 95 percent confidence interval for the difference between proportions l and 2.

Q: Find a 99 percent confidence interval for the difference between means, given that n1 = 49, n2 = 49, = 87, = 92, s12 = 13, and s22 = 15. (Assume unequal variances.)

Q: Calculate the t statistic for testing equality of means where = 8.2, = 11.3, s12 = 5.4, s22 = 5.2, n1 = 6, and n2 = 7. (Assume equal population variances.)

Q: Determine the 95 percent confidence interval for the difference between two population means, where sample 1 has data: 16, 14, 19, 18, 19, 20, 15, 18, 17, 18; and sample 2 has data: 13, 19, 14, 17, 21, 14, 15, 10, 13, 15. (Assume equal population variances.)

Q: Calculate the pooled variance where sample 1 has data: 16, 14, 19, 18, 19, 20, 15, 18, 17, 18; and sample 2 has data: 13, 19, 14, 17, 21, 14, 15, 10, 13, 15.

Q: Sample 1 has data: 16, 14, 19, 18, 19, 20, 15, 18, 17, 18; and sample 2 has data: 13, 19, 14, 17, 21, 14, 15, 10, 13, 15. Testing the equality of means at = .05, can we reject the null hypothesis (using critical value rules)?

Q: We are testing the hypothesis that the proportion of winter-quarter profit growth is more than 2 percent greater for consumer industry companies (CON) than for banking companies (BKG). At = .10, given that CON = .20, BKG = .14, nCON = 300, and nBKG = 400, calculate the estimated standard deviation for the model.

Q: We are testing the hypothesis that the proportion of winter-quarter profit growth is more than 2 percent greater for consumer industry companies (CON) than for banking companies (BKG). At = .10, given that CON = .20, BKG = .14, nCON = 300, and nBKG = 400, can we reject the null hypothesis (using critical value rules)?

Q: When we test H0: 1 - 2 0, HA: 1 - 2 > 0, = 15.4, = 14.5, 1 = 2, 2 = 2.28, n1 = 35, and n2 = 18 at = .01, what is the value of the test statistic?

Q: When we test H0: 1 - 2 0, HA: 1 - 2 > 0, = 15.4, = 14.5, s1 = 2, s2 = 2.28, n1 = 35, and n2 = 18 at α = .01, can we reject the null hypothesis?

Q: Find a 90 percent confidence interval for the difference between the proportions of group l and group 2. Let p1 represent the population proportion of the people in group 1 who like a new mobile app, and let p2represent the population proportion of the people in group 2 who like a new mobile app. 1 = .21, 2 = .13, n1 = 300, and n2 = 400.

Q: Find a 95 percent confidence interval for 1 - 2, where n1 = 9, n2 = 6, = 64, = 59, s12 = 6, and s22 = 3. (Assume equal population variances.)

Q: Find a 95 percent confidence interval for the difference between means, where n1 = 50, n2 = 36, = 80, = 75, s12 = 5, and s22 = 3. Assume unequal variances.

Q: Find a 95 percent confidence interval for the difference between the proportions of older and younger drivers who have tickets, where 1 = .275, 2 = .25, n1 = 1000, and n2 = 1000.

Q: Using a 90 percent confidence interval of [-.0076, .0276] for the difference between the proportions of failures in factory 1 and factory 2, where 1 = .05, 2 = .04, n1 = 500, and n2 = 2000, can we reject the null hypothesis at = .10?

Q: Find a 90 percent confidence interval for the difference between the proportions of failures in factory 1 and factory 2, where 1 = .05, 2 = .04, n1 = 500, and n2 = 2000.

Q: Find a 98 percent confidence interval for the paired difference

Q: Find a 95 percent confidence interval for 1 - 2, where n1 = 15, n2 = 10, = 1.94, = 1.04, s12 = .2025, and s22 = .0676. (Assume equal population variances.)

Q: Find a 95 percent confidence interval for 1 - 2, where n1 = 50, n2 = 75, = 82, = 76, s12 = 8, and s22 = 6. Assume unequal variances.

Q: When we test H0: p1 - p2 .01, HA: p1 - p2 > .01, at = .05, where 1 = .08, 2 = .035, n1 = 200, and n2 = 400, what is the standard deviation used to calculate the test statistic?

Q: When we test H0: p1 - p2 .01, HA: p1 - p2 > .01 at = .05 where 1 = .08, 2 = .035, n1 = 200, and n2 = 400, can we reject the null hypothesis?

Q: When we test H0: 1 2, HA: 1 > 2 at = .10, where = 77.4, = 72.2, s1 = 3.3, s2 = 2.1, n1 = 6, and n2 = 6, what is the estimated pooled variance?

Q: When we test H0: 12, HA: 1 > 2 at = .10, where = 77.4, = 72.2, s1 = 3.3, s2 = 2.1, n1 = 6, and n2 = 6, can we reject the null hypothesis (using critical value rules)? (Assume equal variances.)

Q: When testing H0: 1 - 2 = 2, HA: 1 - 2 > 2, where = 522, = 516, 12 = 28, 22 = 24, n1 = 40, n2 = 30, at = .01, what is the test statistic? (Assume unequal variances.)

Q: When testing H0: 1 - 2 = 2, HA: 1 - 2 > 2, where = 522, = 516, s12 = 28, s22 = 24, n1 = 40, n2 = 30, at = .01, what can we conclude using critical value rules? (Assume unequal variances.)

Q: Construct a 95 percent confidence interval for 1 - 2, where = 34.36, = 26.45, s1 = 9, s2 = 6, n1 =10, n2 =16. (Assume equal population variances.)

Q: In testing the difference between the means of two normally distributed populations, if 1 = 2 = 50, n1 = 9, and n2 = 13, the degrees of freedom for the t statistic equals ___________.A. 22B. 21C. 19D. 20

Q: Given two independent normal distributions with s12 - s22 = 100, 1 = 2 = 50, and n1 = n2 = 50, the sampling distribution of the mean difference - will have a mean of _________.A. 100B. 1C. 0D. 50E. 100

Q: Given the following information about a hypothesis test of the difference between two means based on independent random samples, what is the calculated value of the test statistic? Assume that the samples are obtained from normally distributed populations having equal variances.HA:A > B, = 12,= 9, s1 = 5, s2 = 3, n1 = 13, n2 = 10.A. t = 1.96B. t = 1.5C. t = 2.823D. t = 1.674E. t = 1.063

Q: Given the following information about a hypothesis test of the difference between two means based on independent random samples, what is the standard deviation of the difference between the two means? Assume that the samples are obtained from normally distributed populations having equal variances.HA: A > B, = 12, = 9, s1 = 5, s2 = 3, n1 = 13, n2 = 10.A. 1.792B. 1.679C. 2.823D. 3.210E. 1.478

Q: Given the following information about a hypothesis test of the difference between two variances based on independent random samples, what is the critical value of the test statistic at a significance level of .05? Assume that the samples are obtained from normally distributed populations. A. 3.87 B. 2.67 C. 3.07 D. 2.80 E. 2.38

Q: Two independent samples selected from two normally distributed populations have variances of 12 and22 with n1 = 10 and n2 = 15. The degrees of freedom for the F distribution when testing the equality of the two population variances areA. 10 and 15.B. 11 and 16.C. 9 and 14.D. 8 and 13.

Q: In testing the equality of population variance, what assumption(s) should be considered? A. independent samples B. equal sample sizes C. normal distribution of the populations D. independent samples and equal sample sizes E. independent samples and normal distribution of the populations

Q: Parameters of the F distribution include A. n1. B. degrees of freedom for the numerator and the denominator. C. n2. D. n1 and n2. E. None of the other choices is correct.

Q: In general, the shape of the F distribution is _________. A. skewed right B. skewed left C. normal D. binomial

Q: When comparing two independent population variances, the correct test statistic to use is __________. A. z B. t C. F D. t2

Q: When comparing the variances of two normally distributed populations using independent random samples, the correct test statistic to use is __________. A. z B. t C. F D. chi-square E. None of the other choices is correct.

Q: If we are testing the hypothesis about the mean of a population of paired differences with samples of n1 = 8, n2 = 8, the degrees of freedom for the t statistic is ____. A. 16 B. 7 C. 14 D. 9

Q: The test of means for two related populations matches the observations (matched pairs) in order to reduce the ________________ attributable to the difference between individual observations and other factors. A. means B. test statistic C. degrees of freedom D. variation

Q: In comparing the difference between two independent population means, the sampling distributions of the population means are at least approximately ________________. A. skewed right B. skewed left C. normal D. binomial

Q: In testing the difference between two independent population means, it is assumed that the level of measurement is at least ______________. A. a ratio variable B. a qualitative variable C. an interval variable D. a categorical variable

Q: In testing the difference between two independent population means, if the assumption is of unequal variances, the critical value of the t statistic is obtained by calculating the ___________________. A. degrees of freedom B. sum of the two sample sizes (n1 + n2) C. p-value D. pooled variance

Q: In testing the difference between the means of two independent populations, the variances of the two samples can be pooled if the population variances are assumed to ____________. A. be unequal B. be greater than the mean C. sum to 1 D. be equal

Q: In order to test the effectiveness of a drug called XZR designed to reduce cholesterol levels, the cholesterol levels of 9 heart patients are measured before they are given the drug. The same 9 patients use XZR for two continuous months. After two months of continuous use, the cholesterol levels are measured again. The comparison of cholesterol levels before versus after the administration of the drug is an example of testing the difference between two ____________. A. samples of equal variances B. independent samples C. paired samples D. samples of unequal variances

Q: When testing the difference for the population of paired differences in which two different observations are taken on the same units, the correct test statistic to use is ____. A. z B. t C. F D. t2

Q: An experiment in which two different measurements are taken on the same units and inferences are made using the differences between the pairs of measurements is a(n) ______ experiment.A. paired differenceB. equal variancesC. independent samplesD. dependent samples

Q: An experiment in which there is no relationship between the measurements on the different samples is a(n) ______ experiment. A. paired difference B. equal variances C. independent samples D. dependent samples

Q: When comparing two independent population means by using samples selected from two independent, normally distributed populations with equal variances, the correct test statistic to use is ______. A. z B. t C. F D. t2

Q: When testing the difference between two population proportions, the _______ test statistic is used. A. z B. t C. F D. t2

Q: Given the following information about a hypothesis test of the difference between two means based on independent random samples, which one of the following is the correct rejection region at a significance level of .05?HA: A > B, = 12, = 9, s1 = 4,s2 = 2, n1 = 13, n2 = 10.A. Reject H0 if t > 1.96.B. Reject H0 if t > 1.645.C. Reject H0 if t > 1.721.D. Reject H0 if t > 2.08.E. Reject H0 if t > 1.782.

Q: In which of the following tests is the variable of interest the difference between the values of the observations from the two samples, rather than the actual observations themselves? A. a test of hypothesis about the mean of a population of paired differences selected from two related samples B. a test of hypothesis about the difference between the means of two normally distributed populations using independent samples C. a test of hypothesis about the difference between two population proportions, using large independent random samples D. a test of hypothesis about the difference between the variances of two normally distributed populations using independent samples

Q: If we are testing the difference between the means of two normally distributed independent populations with samples of n1 = 10, n2 = 10, the degrees of freedom for the t statistic is ______.A. 19B. 18C. 9D. 8E. 20

Q: If we are testing the hypothesis about the mean of a population of paired differences with samples of n1 = 10, n2 = 10, the degrees of freedom for the t statistic is ____. A. 19 B. 18 C. 9 D. 8 E. 10

Q: In testing the difference between two means from two normally distributed independent populations, the distribution of the difference in sample means will beA. normally distributed only if sample sizes are equal.B. normally distributed only if both population standard deviations are known.C. normally distributed.D. normally distributed if both sample sizes are very large.E. normally distributed only if both population variances are equal.

Q: A financial analyst working for a financial consulting company wishes to find evidence that the average price-to-earnings ratio in the consumer industry is higher than the average price-to-earnings ratio in the banking industry. The alternative hypothesis isA. consumer = banking.B. consumer banking.C. consumer > banking.D. consumer < banking.E. consumer banking.

Q: When testing the difference between two population proportions using large independent random samples, the __________ test statistic is used. A. z B. t C. F D. chi-square E. None of the other choices is correct.

Q: When testing a hypothesis about the mean of a population of paired differences in which two different observations are taken on the same units, the correct test statistic to use is _________. A. z B. t C. F D. chi-square E. None of the other choices is correct.

Q: A new company is in the process of evaluating its customer service. The company offers two types of sales: (1) Internet sales and (2) store sales. The marketing research manager believes that the Internet sales are more than 10 percent higher than store sales. The alternative hypothesis for this problem would be stated asA. PInternet - Pstore > 0.B. PInternet - Pstore < 0.C. PInternet - Pstore 0.D. PInternet - Pstore .10.E. PInternet - Pstore > .10.

Q: In testing the difference between the means of two normally distributed populations using independent random samples, the correct test statistic to use is the A. z statistic. B. t statistic. C. F statistic. D. chi-square statistic. E. None of the other choices is correct.

Q: In order to test the effectiveness of a drug called XZR designed to reduce cholesterol levels, the cholesterol levels of 9 heart patients are measured before they are given the drug. The same 9 patients use XZR for two continuous months. After two months of continuous use, the cholesterol levels are measured again. The comparison of cholesterol levels before versus after administering the drug is an example of testing the difference between A. two means from independent populations. B. two population variances from independent populations. C. two population proportions. D. matched pairs from two dependent populations.

Q: A new company is in the process of evaluating its customer service. The company offers two types of sales: (1) Internet sales and (2) store sales. The marketing research manager believes that the Internet sales are more than 10 percent higher than store sales. The null hypothesis would beA. PInternet - Pstore > .10.B. PInternet - Pstore < .10.C. PInternet - Pstore .10.D. PInternet - Pstore .10.E. PInternet - Pstore = .10.

Q: In testing for the equality of means from two independent populations, if the hypothesis of equal population means is rejected at = .01, it will __________ be rejected at = .05.A. alwaysB. sometimesC. never

Q: The value of Fα in a particular situation depends on the size of the right-hand tail area and on the numerator degrees of freedom.

Q: The exact shape of the curve of the F distribution depends on two parameters, df1 and df2.

Q: The F statistic can assume either a positive or a negative value.

Q: In testing the difference between two population variances, it is a common practice to compute the F statistic so that its value is always greater than or equal to one.

Q: When comparing the variances of two normally distributed populations using independent random samples, if , the calculated value of F will always be equal to one.